Abstract: Photothermal therapy has emerged as a potential modality to generate hyperthermia as cancer treatment, justified by its low invasiveness and its capacity to complement other cancer therapies. Undesired side effects have been encountered,  related mainly to surrounding healthy tissue damage and temperature increase to values that cause tissue carbonization and evaporation. For this reason, this research aims the development of a multivariable fuzzy logic controller which objective is to maximize tumor thermal damage but always trying to keep temperature in between the recommended ranges and minimize neighboring healthy tissue damage. Three inputs were contemplated for the control system (tumor thermal damage, future maximum temperature error and future healthy tissue temperature error),  thirteen logic rules were used and the controller output was the laser power. It is considered that the control algorithm accomplishes the proposed goals.